Water heater and method of constructing the same

ABSTRACT

A small, inexpensive water heater is disclosed, of the type which uses an atmospheric burner to heat the water, together with a method for making the same from lightweight sheet metal material. According to the method, an elongated heater tube having open and closed ends thereon, is inserted into a liquid container having an opening in the wall thereof. The open end portion of the tube is connected to the wall of the container about the opening so that the opening is closed to the interior of the container while the bore of the tube is placed in communication with the exterior of the container therethrough. The closed end portion of the tube is extended below the operational level of liquid in the container so that the bore of the tube forms an elongated gas flow chamber for heating the liquid therein. Moreover, a baffle is mounted in the bore of the tube so as to separate the upper and lower portions of the chamber for a substantial distance along the length of the tube from the open end thereof. A fuel burner is interconnected with the lower portion of the chamber adjacent the open end portion of the tube so that hot gases can be fed along the bottom of the chamber in the direction of the closed end portion of the tube. A flue is interconnected with the open end portion of the tube adjacent the upper portion of the chamber so that the hot gases are withdrawn along the top of the chamber in the direction of the open end portion of the tube.

United States Patent [191 Wariner Apr. 9, 1974 WATER HEATER AND METHODOF CONSTRUCTING THE SAME [75] lnventor: Derek C. Wariner, Fremont,Calif.

[73] Assignee: National Steel Construction Co.,' Newark, Calif.

22 Filed: Feb. 5, 1969 [21] Appl. No.: 796,655

[52] US. C1,... 122/136, 126/360 [51] Int. Cl. F22b 7/00 [58] Field ofSearch 122/135, 136, 149;

[.56] References Cited 1 UNITED STATES PATENTS 3,527,260 9/1970 Kimmel.122/136 1,701,835 2/1929 Cannon et al. 122/149 1,795,832 3/1931 Cannon122/136 2,729,200 1/1956 Miller 122/149 X 2,737,175 3/1956 Dunston[26/360 3,028,843 4/1962 Carlson et al 122/149 Primary Examiner--KennethW. Sprague Attorney, Agent, 0r Firm--Christensen and Sanborn [57]ABSTRACT A small, inexpensive water heater is disclosed, of the typewhich uses an atmospheric burner to heat the water, together with amethod for making the same from lightweight sheet metal material.According to the method, an elongated heater tube having open and closedends thereon, is inserted into a liquid container having an opening inthe wall thereof. The open end portion of the tube is connected to thewall of the container about the opening so that the opening is closed tothe interior of the container while the bore of the tube is placed incommunication with the exterior of the container therethrough. Theclosed end portion of the tube is extended below the operational levelof liquid in the container so that the bore of the tube forms anelongated gas flow chamber for heating the liquid therein. Moreover, abaffle is mounted in the bore of the tube so as to separate the upperand lower portions of the chamber for a substantial distance along thelength of the tube from the open end thereof. A fuel burner isinterconnected with the lower portion of the chamber adjacent'the openend portion of the tube so that hot gases can be fed along the bottom ofthe chamber in the direction of the closed end portion of the tube. Aflue is interconnected with the open end portion of the tube adjacentthe upper portion of the chamber so that the hot gases are withdrawnalong the top of the chamber in the direction of the open end portion ofthe tube.

23 Claims, 3 Drawing Figures WATER HEATER AND METHOD OF CONSTRUCTING THESAME Field of the Invention This invention relates to liquid heaters andto methods for making the same. In particular, it relates to a waterheater of the type which employs an atmospheric burner to heat thewater, and to a method for making a heater of this type lightweightsheet metal material. The invention is especially applicable, althoughnot exclusively, to the production of small, inexpensive water heatersof this type which are used in mobile homes, travel trailers, and thelike.

BACKGROUND OF THE INVENTION INCLUDING CERTAIN OBJECTS THEREOF The mobilehome and travel trailer industry is a highly competitive industry inwhich both the cost and the weight of the product are highlydeterminative of its salability to the consumer. For this reason,inexpensive, lightweight sheet metal material is widely used in theconstruction of the trailer cabs, as well as in the construction ofappurtenances such as water heaters which are included with thetrailers, or separately sold for the use therewith.

One object of the present invention is to devise a small-sized waterheater of the foregoing type, and a method for making the same, whereinthe heater is especially suited for use in mobile homes, travel trailersand the like, and can be made at acost and weight that are materiallyreduced from the costs and weights which characterized earlier heatersof this type. Another object is to devise a heater and method of thisnature wherein the heater parts or components are constructed fromlight-weight sheet metal material, and are quickly and easily assembledwith one another to form a structural unit which requires only a smallnumber of welds and/or mechanical fasteners to secure it againstvibration. A further object is to devise a heater and method of thisnature wherein the foregoing parts or components are assembled by asystem of slidable or telescopic connections therebetween which quicklyinterengage and align the parts with one another so that little skilland time are needed to assemble the unit. A still further object is todevise a heater and method of this nature wherein most of these partsare preassembled in a small number of separate subassemblies, which arethen post-assembled by a system of telescopic connections therebetweenwhich require little time and skill, and only a few welds and/ormechanical fasteners to secure them against vibration. Other objectsinclude the provision of a heater and method of this nature whereintheforegoing parts and subassemblies are efficiently and compactlyarranged with one another, so as to minimize the space and insulationrequirements for the unit; and wherein the unit is more efficient inoperation than are other units of this type on the market; and moreover,is capable of being readily disassembled should it be necessary torepair or replace one or more of the parts or subassemblies in the unit.Still further objects will become apparent from the description of theinvention which follows hereafter.

SUMMARY OF THE INVENTION These objects and advantages are realized by asmall,

inexpensive, sheet metal water heater of the foregoing type, and amethod for making the same, of my invention, wherein an elongated heatertube having open and closed ends thereon, is inserted into a liquidcontainer having an opening in the wall thereof; and the open endportion of the tube is connected to the wall of the container about theopening so that the opening is closed to the interior of the containerwhile the bore of the tube is placed in communication with the exteriorof the container therethrough. The closed end portion of the tube isextended below the operational level of liquid in the container so thatthe bore of the tube forms an elongated gas flow chamber for heating theliquid therein. Moreover, a baffle is mounted in the bore of the tube soas to separate the upper and lower portions of the chamber for asubstantial distance along the length of the tube from the open endthereof. A fuel burner is interconnected with the lower portion of thechamber adjacent the open end portion of the tube so that hot gases canbe fed along the bottom of the chamber in the direction of the closedend portion of the tube. A flue is interconnected with the open endportion of the tube adjacent the upper portion of the chamber so thatthe hot gases are withdrawn along the top of the chamber in thedirection of the open end portion of the tube.

The heater tube may be integral with the wall of the container, as forexample, where it is extruded from the inner face of the wall to formthe opening therein; or it may be separately fabricated and laterinterconnected with the wall, as for example, where it is welded to thewall about the periphery of the opening therein. Preferably, the tube isa separate item and is slidably inserted in the opening andinterconnected to the wall at the edges thereof.

The body of the flue may be aligned with the tube, or it may be arrangedat an angle thereto. Preferably, the body of the flue is arranged at anupright angle to the tube, and the baffle is projected into the mouth ofthe flue so as to direct the hot gases from the chamber upwardly intothe flue.

Also, the body of the flue maybe supported on the tube and/or separatelytherefrom. Preferably, the open end portion of the tube is passedthrough the opening in the wall of the container, and thence projectedrelatively outwardly therefromyand the body of the flue is supported inan upright disposition on the projecting portion of the tube.

The body of the flue may also be interengaged with the tube, so as tosecure it against vibration thereon. Preferably, the projecting portionof the tube is slidably engaged in the mouth of the flue, between thebaffle and the body of the flue.

In addition, the bafi'le may be interconnected with the body of the flueso as to expedite the mounting thereof. Preferably, the baffle iscantilevered from the body of the flue, and is slidably engageable inthe bore of the tube, so that the flue can be readily mounted on thetube by bayoneting the baffle into the bore of the tube until theprojecting portion of the tube is received in the mouth of the flue.

The mounting process is also expedited if the body of the flue is guidedinto abutmentwith a stop, to indicate that the projecting portion of thetube is engaged in the mouth thereof. Preferably, the flue is thereafterattached to the stop.

In the preferred embodiments of the invention, the flue is attached to amounting frame interposed between the wall of the container and the bodyof the flue. The frame has an opening therein through which theprojecting portion of the heater tube is passed, and thence projectedrelatively outwardly therefrom, so that the flue can be carried thereon.In addition, the frame has a slotted heat shield formed thereon intowhich the body of the flue is guided until it abuts with the frame. Theprojecting portion of the tube is cylindrical in cross section and thebody of the flue has a part cylindrical cutout therein which engages theopen end portion of the tube as the baffle engages in the bore thereof.

In these embodiments, the projecting or cantilevered portion of the tubeis also slidably engageable in the opening of the frame so that thewhole system of components can be quickly and easily assembled on theframe by inserting the tube in the opening thereof until the containerabuts the adjacent side of the frame, and then bayoneting the baffleinto the bore of the tube from the other side of the frame and fasteningthe flue thereto.

The container is supported in a raised condition on the frame by anadditional frame which is intcrengaged with a pair of lugs on thecontainer. After the container has been mounted on the first-mentionedframe, the other frame is slidably engaged on the lugs to support thecontainer in a condition of suspension therebetween. Preferably, thelugs take the form of nipples projecting from the inlet and outlet portsof the container.

The container is also enclosed in spaced relationship within aninsulative jacket having the frames at opposite ends thereof. Usually aninsulative flller is packed into the space between the container and thejacket. The jacket consitututes a longitudinal section of an elongatedopen ended tubular housing having the firstmentioned frame disposed atan intermediate point therein. The opening in the frame for the tube iseccentrically located with respect to the longitudinal axis of thehousing so that the fuel burner controls can be mounted on the frame toone side of the flue.

The burner is suspended from the flue and has a right angular bendtherein so that the inlet end of the burner is quickly and easilyattached to the fuel controls when the flue is mounted on the tube. Inaddition, the baffle is cantilevered from the bottom of the flue so asto form a septum between the burner and the mouth of the flue. Thebaffle is cantilevered by means which effectively thermally insulate itfrom the flue, however, so as to minimize the heat loss thereto.

The forward or free end of the baffle has an upturned flange thereon tocontrol the reentrant flow of the gases in the closed end portion of thetube.

BRIEF DESCRIPTION OF THE DRAWINGS These and other features of theinvention will be better understood by reference to the accompanyingdrawings which illustrate one of the preferred embodiments of theinvention. In the drawings:

FIG. I is a longitudinal cross-sectional view of a water heater unitwhen the unit is mounted in use;

FIG. 2 is a front elevational view of the unit with portions thereofremoved to illustrate the interior of the unit; and

FIG. 3 is a part perspective view of the unit with certain of theinterior components exploded therefrom to improve the illustrationthereof.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings, itwill be seen that the unit comprises an elongated open-ended tubularsheet metal housing 2, the right-hand end portion of which in FIG. 1forms an insulative jacket 4 for a cylindrical water tank 6 enclosed inspaced relationship therewithin. The contents of the tank areatmospherically heated by an elongated cylindrical sheet metal heatertube 8 which is inserted into the tank through an opening 10 in one endwall thereof, and is closed at its inserted end 8. The open end portion8" of the tube rests in an opening 12 formed in the bottom panel 14 ofan open-faced sheet metal box frame 16 which is inserted in and weldedto the left-hand end portion of the housing. Mounted in the recess ofthe frame on the opposite side of the panel 14 from the tank, is a sheetmetal box flue 18 which has a sheet metal baffle 20 cantilevered fromthe mouth 22 thereof into the bore of the tube. The bore of the tubeforms an elongated gas flow chamber 24 for the hot gases of combustionfrom a propane gas burner 26 suspended from the flue. The gases undergoreentrant flow around the baffle, firstly, along the bottom of thechamber in the direction of the closed end portion 8' of the tube, andthence along the top of the chamber in the direction of the open endportion 8" of the tube. Thus, all sides of the tube are heated by thegases and the heat in turn escapes into the water which is continuallycirculated through inlet and outlet ports 28 and 30 in the right-handend of the tank. The ports have nipples 32 welded therein which in turnhave couplings 34 threaded thereon that rest in holes 36 in a flangedcover panel 38 applied as a cap over the right-hand end of the housing.The left-hand end of the housing is also capped by .a similar coverpanel 40 which is appliedover the face of the frame 16. The apertures inthe latter panel includes a pair of elongated horizontal slots, one ofwhich 42 is disposed near I the bottom of the panel to admit fresh airabout the burner, and the other of which 44 is disposed near the top ofthe pannel to discharge the exhaust gases from the flue.

Typically, the heater unit is little more than 2 feet in length and islight enough for a man to pick up in his arms. When installed in use,for example, in a mobile home or travel trailer, the unit is generallyplaced on a narrow shelf or platform 46 which is disposed at one side ofthe vehicle and opens to that side through a slot 48 in the cab 50 ofthe vehicle. The slot is sized so that the unit can be inserted andwithdrawn through it, and when installed, the unit is disposed so thatthe recess of the frame is accessible through the slot when the coverpanel is removed.

The tank is fabricated from a cylindrical shell 52 to which a pair ofdished plates 54 and 56 are welded to give it a closed prolateconstruction at the ends. The plates are apertured, however, to providethe necessary openings for the tube 8 and the inlet and outlet nipples32, and each of these is slidably inserted in its opening and welded tothe periphery thereof. In the case of the tube, the opening 10 is formedat an eccentric location with respect to the longitudinal axis of thetank, and the open end portion 8" of the tube is passed through theopening, and projected relatively outwardly therefrom. The openings 28and 30 for the nipples are disposed relatively adjacent the bottom andthe top of the tank, respectively.

The flue 18 has an orthogonal cross section and is constructed fromseveral pieces of sheet metal, one 58 of which has the shape of achannel, the sides 60 of which are angularly truncated at the top. Theback 62 of the channel has a greater width than the outer diameter ofthe tube 8, and is cutaway and bent forwardly from the sides 60 at theangle of truncation. A second piece 64 is webbed across the open face ofthe channel, bent forwardly against the truncated edges of the sides,and secured to the channel 58 by welding. The flanks of the web projectoutwardly from the sides of the channel to form flanges 66 for theattachment of the flue to the bottom 14 of the frame. In addition, apair of fillets 68 and 70 are added between the web 64 and the back 62of the channel to close one side of the canted portion 18 of the flue,so that the flue gases are deflected into a course inclined moretangentially to the discharge slot 44 in the cover panel 40 of thehousing. The opposite side of the canted portion is unclosed, however,with the exception of a short lip 72 which is formed on the adjacentedge of the web.

The baffle is cantilevered from the back 62 of the channel through asemi-circular cutout 74 removed from the bottom edge of the web 64. Thecutout corresponds in diameter to the outside diameter of the heatertube, whereas the baffle has a width corresponding to the insidediameter of the tube. Uptumed flanges 76 and 78 are formed at the endsof the baffle, and the rear flange 76 is bolted to the back of thechannel by means of two pairs of nuts 80 and bolts 82. Also, anadditional pair of nuts 84 is interposed on the bolts between the flange76 and the channel so that the baffle and the-flue are effectivelyspaced from one another on all sides.

The upturned flange 78 on the forward or free end of the baffle is bentslightly toward the flue.

The propane gas burner 26 is formed by a metal tube 86 and a nozzle 88threaded into the rear end thereof. The tube and nozzle are each bentthrough a right angle turn, and the unthreaded end of the nozzle isequipped with a nut 90 for making a slip fitting with a U-shaped gasfeed tube 92 emanating from the fuelcontrol system 94 for the burner. Inaddition, the burner tube 86 has a pair of mutually opposingcircumferential slots 96 therein, upstream from the nozzle, which act asan air intake for the gas when it is discharged into the burner in use.

Theburner is suspended in a horizontal disposition from the back of theflue by means of a right angled tab 98 welded to the discharge end ofthe tube 86. The tab has a hole 100 therein for receiving one of thebolts 82 used in connecting the baffle and theflue, and when the baffleand flue are interconnected with one another, the tab is insertedbetween them and simultaneously bolted into place under the baffle. Thebaffle thus acts as a septum between the burner and the mouth 22 of theflue.

The fuelcontrol system 94 for the burner forms no specific part of theinvention and need not be discussed in detail other than to say that itis mounted on the frame by means of a threaded nipple (not shown)projecting from the bottom thereof, and includes a pair of pilotcontrols 102 which are extended into the mouth of the heater tube forignition of the burner.

The box frame 16 is slightly canted at the sides to facilitate weldingit to the housing, and is flanged at the rim 104 to abut the end of thehousing when it is installed. Clips 106 behind notches 108 in the rimprovide for mounting the cover panel 40 thereon. In addition, the upperside of the frame has a built-up construction thereon comprising severallayers of sheet metal which are loosely sandwiched with one another toform a heat shield 1 10 that projects out the discharge slot 44 of thepanel. The upper side of the housing 2 is cut back to accommodate theshield, and sheet metal screws 112 rather than welds, are used tointerconnect the cover flap 114 of the shield with the housing. Theshield absorbs and dissipates the heat from the flue to safeguard thecab 50 of the trailer from scorching or other damage, and also has sideskirts 116 thereon which guide the flue into position as it is mountedon the tabs. The skirts control the discharge of the gases from theflue, and assure that they fan out over the whole width of the slot 44in the panel.

The box frame also has a small right angle tab 118 welded to the lowerright-hand corner thereof (FIG. 3), to which a right angle sheet metalburner shield 120 is secured between the burner and the cover panel.

The foregoing components are quickly and easily assembled with oneanother. In advance of the operation, the heater tube and container arepreassembled with one another, as are the flue, the baffle and theburner. The burner controls 94 are mounted in the box frame, and as thefirst step in the assembly operation, the frame is inserted in theleft-hand end of the housing and welded to it from within the housing.The flap 114 may also be attached at this time. Next, the housing 2 isturned up on end and rested on the frame, the tank and tube assembly isinserted in the housing, and theprojecting portion 8" of the tube isslidably engaged in the opening 12 of the frame. An insulative filler124 is also packed about the tank at this time. Then, the couplings 34are applied to the nipples, and the rear cover panel 38 is engaged onthe couplings and secured to the upturned end of the-housing by means ofscrews 126. Thereafter, the housing is placed in a horizontal positionon a table or stand, and the open face of the frame is turned to view.The pilot controls 102 are inserted in the bottom of the tube, and theburner, flue, and baffle assembly is gripped in one hand and mounted onthe tube byguiding the canted portion 18 of the flue between the skirts116 of the shield while the baffle 20 is bayoneted into the bore of thetube. The projecting portion 8" of the tube engages in the mouth 22 ofthe flue, between the baffle and. the body of the web 64, and when theweb abuts both the bottom of the frame and the right-hand skirt, theassembly is in position to be secured to the frame by means of screws128 in the flanges 66 of the web. The burner 26 is also in position tobe attached to the U-shaped fuel supply tube 92 by means of the slipfitting. Thereafter, the burner shield 120 is slipped under the pilotcontrols and attached to the tab 118, and the front cover panel 40 isapplied over the rim 104 of the frame and secured to the two clips 106.

When the unit is put into use, the front cover panel 40 is easilyremoved to hook up the fuel supply 130 to the controls. In addition, thewater supply and discharge lines 132 and 134 are threaded to thecouplings 34,

and normally it is not necessary to remove the rear cover panel 38 inthis connection.

I claim:

1. A water heater of the type wherein an atmospheric burner is used toheat the water, comprising a liquid container having an opening in thewall thereof, an elongated immersion heater tube having open and closedends thereon, inserted generally horizontally into the container andhaving the open end portion thereof connected to the wall of thecontainer about the opening therein so that the opening is closed to theinterior of the container while the bore of the tube is placed incommunication with the exterior of the container therethrough, and formsan elongated gas flow chamber for heating the liquid in the container, aflat baffle inserted generally horizontally into the bore of the tubefor a substantial distance along the length of the tube inwardly fromthe open end thereof, but terminating short of the closed end of thetube, so as to separate the lower and upper portions of the chamber forreentrant flow of the gases therethrough, a fuel burner nozzle arrangedin communication with the lower portion of the chamber adjacent the openend portion of the tube so that the hot gases therefrom are fed alongthe bottom of the chamber in the direction of the closed end portion ofthe tube, and a flue interconnected with the open end portion of thetube adjacent the upper portion of the chamber so that the hot gasestherein are withdrawn along the top of the chamber in the direction ofthe open end portion of thetube, the open end portion of the tubepassing through the opening in the wall of the container, and thenceprojecting relatively outwardly therefrom, and the body of the fluebeing supported in an upright disposition on the projecting portion ofthe tube.

2. The water heater according to claim 1 wherein the heater tube isslidably inserted in the opening in the container wall andinterconnected to the wall at the edge thereof.

3. The water heater according to claim 1 wherein the body of the flue isarranged at a right angle to the tube, and the baffle is projected intothe mouth of the flue so as to direct the hot gases from the chamberupwardly into'the flue.

4. The water heater according to claim 1 wherein the projecting portionof the tube is slidably engaged in the mouth of the flue, betweenthebaffle and the body of the flue.

S. The water heater according to claim 4 wherein the baffle iscantilevered from the body of the flue, and slidably engaged in the boreof the tube.

6. The water heater according to claim 4 wherein the flue is alsoattached to a stop in abutment therewith.

7. The water heater according to claim 6 wherein the flue is attached toa mounting frame interposed between the wall of the container and thebody of the flue.

8. The water heater according to claim 7 wherein the frame has anopening therein, and the projecting portion of the heater tube passesthrough the opening in the frame, and thence projects relativelyoutwardly therefrom, with the flue carried thereon.

9. The water heater according to claim 8 wherein the frame has a slottedheat shield formed thereon into which the body of the flue is insertedin abutment with the frame.

10. The water heater according to claim 8 wherein the projecting portionof the tube is cylindrical in cross section, and the body of the fluehas a part cylindrical cutout therein which engages the open end portionof the tube.

11. The water heater according to claim 8 wherein the projecting portionof the tube is slidably engaged in the opening of the frame.

12. The water heater according to claim 7 wherein the container issupported in a raised condition on the frame by an additional frameinterengaged with a pair of lugs on the container.

13. The water heater according to claim 12 wherein the lugs are slidablyengaged in holes in the additional frame, and the container is supportedin a condition of suspension between the frames.

14. The water heater according to claim 13 wherein the lugs take theform of nipples projecting from the inlet and outlet ports of thecontainer.

15. The water heater according to claim 12 wherein the container isenclosed in spaced relationship within an insulative jacket having theframes at opposite ends thereof.

16. The water heater according to claim 5 wherein the jacket constitutesa longitudinal section of an elongated, open ended tubular housinghaving the first mentioned frame disposed at an intermediate pointtherein.

17. The water heater according to claim 16 wherein the opening in theframe for the tube, is eccentrically located with respect to thelongitudinal axis of the housing.

18. In a water heater of the type wherein an atmospheric burner is usedto heat the water, a liquid container having an opening in the wallthereof, an elongated cylindrical immersion heater tube having open andclosed ends thereon, inserted generally horizontally into the containerand having the open end portion thereof connected to the wall of thecontainer about the opening therein so that the opening is closed to theinterior of the container while the bore of the tube is placed incommunication with the exterior of the container therethrough, and formsan elongated gas flow chamber for heating the liquid in the container,and a flat baffle inserted in the bore of the tube for a substantialdistance along the length of the tube inwardly from the open tubethereof, but terminating short of the closed end of the tube, so as toseparate the lower and upper portions of the chamber for reentrant flowof the gases therethrough, said baffle being disposed substantially inthe horizontal diametral plane of the tube and having a width slightlyless than thediameter of the bore, so that it is longitudinally slidablysupported therein, and the forwardly inserted end. of the baffle havingan upturned flange thereon to control the reentrant flow of the gases inthe closed end portion of the tube.

19. The water heater according to claim 18 wherein the open end portionof the tube passes through the opening in the wall of the container, andthence projects relatively outwardly therefrom.

20. The water heater according to claim 19 wherein the rearward end ofthe baffle projects relatively outwardly beyond the open end of thetube.

21. A water heater of the type wherein an atmospheric burner is used toheat the water, comprising a liquid container having an opening in thewall thereof,

an elongated immersion heater tube having open and closed ends thereon,inserted generally horizontally into the container and having the openend portion thereof connected to the wall of the container about theopening therein so that the opening is closed to the interior of thecontainer while the bore of the tube is placed in communication with theexterior of the container therethrough, and forms an elongated gas flowchamber for heating the 'liquid in the container, a flat baffle insertedgenerally horizontally into the bore of the tube for a substantialdistance along the length of the tube inwardly from the open endthereof, but terminating short of the closed end of the tube, so as toseparate the lower and upper portions of the chamber for reentrant flowof the gases therethrough, a fuel burner arranged in communication withthe lower portion of the chamber adjacent the open end portion of thetube so that the hot gases therefrom are fed along the bottom of thechamber in the direction of the closed end portion of the tube, and aflue interconnected with the open end portion of the tube adjacent theupper portion of the chamber so that the hot gases therein are withdrawnalong the top of the chamber in the direction of the open end portion ofthe tube, the fuel burner being suspended from the flue and having aright angular bend therein so as to extend toward one side of the flue.

22. A water heater of the type wherein an atmospheric burner is used toheat the water, comprising a liquid container having an opening in thewall thereof, an elongated immersion heater tube having open and closedends thereon, inserted generally horizontally into the container andhaving the open end portion thereof connected to the wall of thecontainer about the opening therein so that the opening is closed to theinterior of the container while the bore of the tube is placed incommunication with the exterior of the container therethrough, and formsan elongated gas flow chamber for heating the liquid in the container, aflat baffle inserted generally horizontally into the bore of the tubefor a substantial distance along the length of the tube inwardly fromthe open end thereof, but terminating short of the closed end of thetube, so as to separate the lower and upper portions of the chamber forreentrant flow of the gases therethrough, a fuel burner arranged incommunication with the lower portion of the chamber adjacent the openend portion of the tube so that the hot gases therefrom are fed alongthe bottom of the chamber in the direction of the closed end portion ofthe tube, and a flue interconnnected with the open end portion of thetube adjacent the upper portion of the chamber so that the hot gasestherein are withdrawn along the top of the chamber in the direction ofthe open end portion of the tube, the baffle being cantilevered from thebottom of the flue by means which effectively thermally insulate it fromthe flue, so as to form a septum between the burner and the mouth of theflue.

23. A water heater of the type wherein an atmospheric burner is used toheat the water, comprising a liquid container having an opening in thewall thereof, an elongated immersion heater tube having open and closedends thereon, inserted generally horizontally into the container andhaving the open end portion thereof connected to the wall of thecontainer about the opening therein so that the opening is closed to theinterior of the container while the bore of the tube is placed incommunication with the exterior of the container therethrough, and formsan elongated gas flow chamber for heating the liquid in the container, aflat baffle inserted generally horizontally into the bore of the tubefor a substantial distance along the length of the tube inwardly fromthe open end thereof, but terminating short of the closed end of thetube, so as to separate the lower and upper portions of the chamber forreentrant flow of the gases therethrough, a fuel burner arranged incommunication with the lower portion of the chamber adjacent the openend portion of the tube so that the hot gases therefrom are fed alongthe bottom of the chamber in the direction of the closed end portion ofthe tube, and a flue interconnected with the open end portion of thetube adjacent the upper portion of the chamber so that the hot gasestherein are withedrawn along the top of the chamber in the direction ofthe open end portion of the tube, the forward end of the baffle havingan upturned flange thereon to control the reentrant flow of the gases inthe closed end portion of the tube.

1. A water heater of the type wherein an atmospheric burner is used toheat the water, comprising a liquid container having an opening in thewall thereof, an elongated immersion heater tube having open and closedends thereon, inserted generally horizontally into the container andhaving the open end portion thereof connected to the wall of thecontainer about the opening therein so that the opening is closed to theinterior of the container while the bore of the tube is placed incommunication with the exterior of the container therethrough, and formsan elongated gas flow chamber for heating the liquid in the container, aflat baffle inserted generally horizontally into the bore of the tubefor a substantial distance along the length of the tube inwardly fromthe open end thereof, but terminating short of the closed end of thetube, so as to separate the lower and upper portions of the chamber forreentrant flow of the gases therethrough, a fuel burner nozzle arrangedin communication with the lower portion of the chamber adjacent the openend portion of the tube so that the hot gases therefrom are fed alongthe bottom of the chamber in the direction of the closed end portion ofthe tube, and a flue interconnected with the open end portion of thetube adjacent the upper portion of the chamber so that the hot gasestherein are withdrawn along the top of the chamber in the direction ofthe open end portion of the tube, the open end portion of the tubepassing through the opening in the wall of the container, and thenceproJecting relatively outwardly therefrom, and the body of the fluebeing supported in an upright disposition on the projecting portion ofthe tube.
 2. Th water heater according to claim 1 wherein the heatertube is slidably inserted in the opening in the container wall andinterconnected to the wall at the edge thereof.
 3. The water heateraccording to claim 1 wherein the body of the flue is arranged at a rightangle to the tube, and the baffle is projected into the mouth of theflue so as to direct the hot gases from the chamber upwardly into theflue.
 4. The water heater according to claim 1 wherein the projectingportion of the tube is slidably engaged in the mouth of the flue,between the baffle and the body of the flue.
 5. The water heateraccording to claim 4 wherein the baffle is cantilevered from the body ofthe flue, and slidably engaged in the bore of the tube.
 6. The waterheater according to claim 4 wherein the flue is also attached to a stopin abutment therewith.
 7. The water heater according to claim 6 whereinthe flue is attached to a mounting frame interposed between the wall ofthe container and the body of the flue.
 8. The water heater according toclaim 7 wherein the frame has an opening therein, and the projectingportion of the heater tube passes through the opening in the frame, andthence projects relatively outwardly therefrom, with the flue carriedthereon.
 9. The water heater according to claim 8 wherein the frame hasa slotted heat shield formed thereon into which the body of the flue isinserted in abutment with the frame.
 10. The water heater according toclaim 8 wherein the projecting portion of the tube is cylindrical incross section, and the body of the flue has a part cylindrical cutouttherein which engages the open end portion of the tube.
 11. The waterheater according to claim 8 wherein the projecting portion of the tubeis slidably engaged in the opening of the frame.
 12. The water heateraccording to claim 7 wherein the container is supported in a raisedcondition on the frame by an additional frame interengaged with a pairof lugs on the container.
 13. The water heater according to claim 12wherein the lugs are slidably engaged in holes in the additional frame,and the container is supported in a condition of suspension between theframes.
 14. The water heater according to claim 13 wherein the lugs takethe form of nipples projecting from the inlet and outlet ports of thecontainer.
 15. The water heater according to claim 12 wherein thecontainer is enclosed in spaced relationship within an insulative jackethaving the frames at opposite ends thereof.
 16. The water heateraccording to claim 5 wherein the jacket constitutes a longitudinalsection of an elongated, open ended tubular housing having the firstmentioned frame disposed at an intermediate point therein.
 17. The waterheater according to claim 16 wherein the opening in the frame for thetube, is eccentrically located with respect to the longitudinal axis ofthe housing.
 18. In a water heater of the type wherein an atmosphericburner is used to heat the water, a liquid container having an openingin the wall thereof, an elongated cylindrical immersion heater tubehaving open and closed ends thereon, inserted generally horizontallyinto the container and having the open end portion thereof connected tothe wall of the container about the opening therein so that the openingis closed to the interior of the container while the bore of the tube isplaced in communication with the exterior of the container therethrough,and forms an elongated gas flow chamber for heating the liquid in thecontainer, and a flat baffle inserted in the bore of the tube for asubstantial distance along the length of the tube inwardly from the opentube thereof, but terminating short of the closed end of the tube, so asto separate the lower and upper portions of the chamber for reentrantflow of the gases therethrough, said baffle being disposed substanTiallyin the horizontal diametral plane of the tube and having a widthslightly less than the diameter of the bore, so that it islongitudinally slidably supported therein, and the forwardly insertedend of the baffle having an upturned flange thereon to control thereentrant flow of the gases in the closed end portion of the tube. 19.The water heater according to claim 18 wherein the open end portion ofthe tube passes through the opening in the wall of the container, andthence projects relatively outwardly therefrom.
 20. The water heateraccording to claim 19 wherein the rearward end of the baffle projectsrelatively outwardly beyond the open end of the tube.
 21. A water heaterof the type wherein an atmospheric burner is used to heat the water,comprising a liquid container having an opening in the wall thereof, anelongated immersion heater tube having open and closed ends thereon,inserted generally horizontally into the container and having the openend portion thereof connected to the wall of the container about theopening therein so that the opening is closed to the interior of thecontainer while the bore of the tube is placed in communication with theexterior of the container therethrough, and forms an elongated gas flowchamber for heating the liquid in the container, a flat baffle insertedgenerally horizontally into the bore of the tube for a substantialdistance along the length of the tube inwardly from the open endthereof, but terminating short of the closed end of the tube, so as toseparate the lower and upper portions of the chamber for reentrant flowof the gases therethrough, a fuel burner arranged in communication withthe lower portion of the chamber adjacent the open end portion of thetube so that the hot gases therefrom are fed along the bottom of thechamber in the direction of the closed end portion of the tube, and aflue interconnected with the open end portion of the tube adjacent theupper portion of the chamber so that the hot gases therein are withdrawnalong the top of the chamber in the direction of the open end portion ofthe tube, the fuel burner being suspended from the flue and having aright angular bend therein so as to extend toward one side of the flue.22. A water heater of the type wherein an atmospheric burner is used toheat the water, comprising a liquid container having an opening in thewall thereof, an elongated immersion heater tube having open and closedends thereon, inserted generally horizontally into the container andhaving the open end portion thereof connected to the wall of thecontainer about the opening therein so that the opening is closed to theinterior of the container while the bore of the tube is placed incommunication with the exterior of the container therethrough, and formsan elongated gas flow chamber for heating the liquid in the container, aflat baffle inserted generally horizontally into the bore of the tubefor a substantial distance along the length of the tube inwardly fromthe open end thereof, but terminating short of the closed end of thetube, so as to separate the lower and upper portions of the chamber forreentrant flow of the gases therethrough, a fuel burner arranged incommunication with the lower portion of the chamber adjacent the openend portion of the tube so that the hot gases therefrom are fed alongthe bottom of the chamber in the direction of the closed end portion ofthe tube, and a flue interconnnected with the open end portion of thetube adjacent the upper portion of the chamber so that the hot gasestherein are withdrawn along the top of the chamber in the direction ofthe open end portion of the tube, the baffle being cantilevered from thebottom of the flue by means which effectively thermally insulate it fromthe flue, so as to form a septum between the burner and the mouth of theflue.
 23. A water heater of the type wherein an atmospheric burner isused to heat the water, comprising a liquid container having an openingin the wall thereof, an elOngated immersion heater tube having open andclosed ends thereon, inserted generally horizontally into the containerand having the open end portion thereof connected to the wall of thecontainer about the opening therein so that the opening is closed to theinterior of the container while the bore of the tube is placed incommunication with the exterior of the container therethrough, and formsan elongated gas flow chamber for heating the liquid in the container, aflat baffle inserted generally horizontally into the bore of the tubefor a substantial distance along the length of the tube inwardly fromthe open end thereof, but terminating short of the closed end of thetube, so as to separate the lower and upper portions of the chamber forreentrant flow of the gases therethrough, a fuel burner arranged incommunication with the lower portion of the chamber adjacent the openend portion of the tube so that the hot gases therefrom are fed alongthe bottom of the chamber in the direction of the closed end portion ofthe tube, and a flue interconnected with the open end portion of thetube adjacent the upper portion of the chamber so that the hot gasestherein are withedrawn along the top of the chamber in the direction ofthe open end portion of the tube, the forward end of the baffle havingan upturned flange thereon to control the reentrant flow of the gases inthe closed end portion of the tube.